Experimental Study On The Effects Of Integrin β3 On The Ca～(2+) Channels In DI Detrusor Smooth Muscle Cells

Background and objective: Detrusor instability (DI) is a common micturational dysfunction in urology. The condition is associated with symptoms of urinary frequency, urgency and urge incontinence, and even leads to hydronephrosis or the impairment of the renal function in those serious cases. The exact etiology of detrusor instability has not been unwinded and the main controversy is focused on wether it is neurogenic or myogenic causes. The latest accumulated evidences indicate that detrusor smooth mscle has autorhythemicty, and DI is closely related with the spontaneously enhanced excitability of detrusor and the end stage of detrusor instability is the increased excitability of detrusor smooth muscle cells,which is believed to due to a myogenic alteration of excitability.Ca²⁺ plays a key role in the regulation of the excitability of detrusor smooth muscle cells.At the same time,serving as a second messenger, Ca²⁺ plays an important role in the signal transduction in detrusor cells,and the regulation on the contraction of detrusor smooth muscle depends to a great extent on the regulation of Ca²⁺ ion.The premise of excitation of the detrusor smooth muscle cell is the influx of the extracellular Ca²⁺ ion,then leads to the alteration of the membrane potential,and activates the voltage-gated ion channels and resultes in the membrane depolarization.In addition,the contraction of detrusor muscle depends on the increasing of the concentration of the intracellular Ca²⁺ ion.Integrins are a transmembrane protein family which are composed ofαandβsubunits.They ane not only a kind of adhension molecules, but also participate in a bi-directional signaling.Inside-out signals regulate integrin affinity for adhesive ligands, and ligand-dependent outside-in signals regulate cellular response to adhesion.In the last few years,researchs on the cardiac muscle cells and vascular smooth muscle cells indicate that integrins can regulate the Ca²⁺ current.On account of the above findings,in our study we detected the expression of integrinβ3 subunit in DI detrusor and investigated the effects of integrinβ3 subunit on the Ca²⁺...